**Monday: **Teacher professional day

**Tuesday: **Went over the AP problems from Friday. That took all class. Homework was to continue with whatever problems haven’t been finished, feel free to read!

**Wednesday: **Went over solving stoichiometry problems with only volumes of gases. The big idea is that because a given volume has the same number of particles (moles) at a given P and T, you can treat volumes like moles in stoichiometry problems as long as the pressure and temperature stay the same. (This is for volume to volume problems only.) Next we went over 5.27 and 5.28 from your homework. You talked about it in groups and then we went over a couple of the tricky ideas. 1) the mass of the molecules doesn’t matter when it comes to pressure because the pressure depends only on the # of particles, not their identity. Even heavier gases would have the same pressure (assuming same T and V). If they are at the same temperature, they will have the same energy and therefore will hit the sides with the same amount of force. This leads us to the second tricky idea 2) the mass does affect speed of the molecules. Molecules or atoms at the same temperature have the same kinetic energy (temperature is a measure of kinetic energy). So, since KE = 1/2mv^2, where m = mass and v = velocity or speed, if 2 molecules have the same energy but one has a larger mass, it must have a smaller speed in order to have the same energy. The 3rd tricky idea had to do with surface area. It seems as though molecules in a shape with more surface area would collide with the surface more often and that might make you think the pressure is higher, but Pressure = Force / Area, so the increase in force from additional collisions is balanced by the increase in surface area. We did a few more practice problems involving proportions. We reviewed which variables were inversely and which were directly proportional and also some mole fraction / Dalton’s law problems.

During the second half of class we went over the Dumas method for determining in the molar mass of a volatile gas. This included a discussion of how to think about error analysis when writing your conclusions. We ended with a problem that mixed the Dumas method with empirical and molecular formula.

HW: Finish all your homework!

**Thursday: **Do PhET simulation for gases. Goal is to collect data that shows pressure and volume have an inverse relationship. Include design 1 items from checklist, collect quantitative and qualitative data, graph data and include a discussion that justifies your claim that pressure and volume have an inverse relationship. A second goal is to collect data that shows how absolute zero is derived. You should include items from Design 1 on checklist as well as quantitative and qualitative data (do not measure absolute zero diretly) + a graph showing how you use it to get absolute zero. Your graph need to have the temperature in celsius.

**Friday: **Today we worked on the rest of the AP problems. Some of you worked on a study guide instead. Homework to be collected is all textbook problems and AP Free response problems.